The invention relates to an axial piston machine having a first group of pistons for delivery into a first hydraulic circuit and having a second group of pistons for delivery into a second hydraulic circuit.
From DE 30 26 765 A1 it is known, in an axial piston machine, to provide a first group of pistons and a second group of pistons, which deliver in each case into a separate hydraulic circuit. In order to be able to adjust a different delivery rate each for the first hydraulic circuit and for the second hydraulic circuit, the pistons of the first group and the pistons of the second group are supported in each case on a separate swash plate. The angles of inclination of the two swash plates are adjustable in each case by means of a separate control device.
The pistons of the first group and the pistons of the second group are disposed along, in each case, a separate graduated circle, wherein the pistons that are associated with the graduated circle having the smaller diameter are supported on a first swash plate, which is of a hemispherical design at the side remote from the pistons and is mounted in the second swash plate. The first and the second swash plate, for independent adjustment of the delivery rates of the first hydraulic circuit and the second hydraulic circuit, are pivotable separately about a common axis, wherein for displacing the first swash plate in the second swash plate a recess is provided, through which the control device accesses the first swash plate. The first swash plate, for varying the dead centre position, may moreover be inclined slightly about a second axis that is perpendicular to the actual swiveling axis.
A drawback of this arrangement is that the second swash plate, whilst it may be mounted in a known manner with a spherical external contour, at the same time has to be designed as a bearing for the first swash plate. A further drawback is that, for adjusting the swivel angle of the inner swash plate, a recess is provided in the second swash plate. As the swash plates have to absorb considerable compressive forces, the required recess may be neither fashioned nor positioned in any desired manner. This leads however to a restriction with regard to the displaceability of the first swash plate, with the result that the volumetric displacement of the corresponding hydraulic circuit is also variable only to a limited extent.
Furthermore, by mounting the two swash plates one inside the other, the overall axial length of the axial piston machine is increased. Some of the advantage of using a single axial piston machine to deliver into two hydraulic circuits is therefore sacrificed.